From DE 1 460 639 A, a segment roller of the generic type is known. This consists of a roller body which is mounted rotatably about an axis. Formed on the outer side of this roller body are grooves, into which H-shaped profiles are inserted. These profiles are of elastic configuration and with their outer side clasp a material web. By displacement of the profiles, the material web can be stretched in width. This segment roller forms the basis of the present invention.